feature: use --skip-duplicates to ignore duplicate paths specified from the command line.

Author: ioggstream

AUTHORS

@@ -94,6 +94,7 @@ Punyashloka Biswal
 Quentin Pradet
 Ralf Schmitt
 Raphael Pierzina
+Roberto Polli
 Roman Bolshakov
 Ronny Pfannschmidt
 Ross Lawley

CHANGELOG.rst

@@ -116,8 +116,10 @@ time or change existing behaviors in order to make them less surprising/more use
     fixtures and reports them;
   + ``--setup-show``: performs normal test execution and additionally shows
     setup and teardown of fixtures;
+  + ``--skip-duplicates``: ignore duplicate tests, taking into account only 
+    the first one `#1609`_;
 
-  Thanks `@d6e`_, `@kvas-it`_, `@sallner`_ and `@omarkohl`_ for the PRs.
+  Thanks `@d6e`_, `@kvas-it`_, `@sallner`_, `@ioggstream`_ and `@omarkohl`_ for the PRs.
 
 * New cli flag ``--override-ini``/``-o``: overrides values from the ini file.
   For example: ``"-o xfail_strict=True"``'.
@@ -514,6 +516,7 @@ time or change existing behaviors in order to make them less surprising/more use
 
 .. _`traceback style docs`: https://pytest.org/latest/usage.html#modifying-python-traceback-printing
 
+.. _#1609: https://github.com/pytest-dev/pytest/issues/1609
 .. _#1422: https://github.com/pytest-dev/pytest/issues/1422
 .. _#1379: https://github.com/pytest-dev/pytest/issues/1379
 .. _#1366: https://github.com/pytest-dev/pytest/issues/1366
@@ -539,6 +542,7 @@ time or change existing behaviors in order to make them less surprising/more use
 .. _@rabbbit: https://github.com/rabbbit
 .. _@hackebrot: https://github.com/hackebrot
 .. _@pquentin: https://github.com/pquentin
+.. _@ioggstream: https://github.com/ioggstream
 
 2.8.7
 =====

_pytest/config.py

@@ -155,6 +155,7 @@ def __init__(self):
         self._conftestpath2mod = {}
         self._confcutdir = None
         self._noconftest = False
+        self._duplicatepaths = set()
 
         self.add_hookspecs(_pytest.hookspec)
         self.register(self)

_pytest/main.py

@@ -63,6 +63,9 @@ def pytest_addoption(parser):
     group.addoption('--noconftest', action="store_true",
         dest="noconftest", default=False,
         help="Don't load any conftest.py files.")
+    group.addoption('--skipduplicates', '--skip-duplicates', action="store_true",
+        dest="skipduplicates", default=False,
+        help="Skip duplicate tests.")
 
     group = parser.getgroup("debugconfig",
         "test session debugging and configuration")
@@ -154,7 +157,25 @@ def pytest_ignore_collect(path, config):
     excludeopt = config.getoption("ignore")
     if excludeopt:
         ignore_paths.extend([py.path.local(x) for x in excludeopt])
-    return path in ignore_paths
+
+    if path in ignore_paths:
+        return True
+
+    # Skip duplicate paths. 
+    #  TODO: is this called when specifying direct filenames 
+    #        from command lines, eg. 
+    #        py.test test_a.py test_b.py
+    skipduplicates = config.getoption("skipduplicates")
+    duplicate_paths = config.pluginmanager._duplicatepaths
+    if skipduplicates:
+        if path in duplicate_paths:
+            #  TODO should we log this?
+            return True
+        else:
+            duplicate_paths.add(path)
+
+    return False
+
 
 class FSHookProxy:
     def __init__(self, fspath, pm, remove_mods):

testing/python/collect.py

@@ -1213,3 +1213,25 @@ def test_syntax_error_with_non_ascii_chars(testdir):
         '*SyntaxError*',
         '*1 error in*',
     ])
+
+
+def test_skip_duplicates(testdir):
+    """Test for issue https://github.com/pytest-dev/pytest/issues/1609 (#1609)
+
+    Ignore duplicate test filenames.
+    """
+    a = testdir.mkdir("a")
+    fh = a.join("test_a.py")
+    fh.write(_pytest._code.Source("""
+        import pytest
+        def test_real():
+            pass
+    """))
+    fpath = fh.strpath
+    result = testdir.runpytest("--skip-duplicates", a.strpath, a.strpath)
+    result.stdout.fnmatch_lines([
+        '*collected 1 item*',
+    ])
+
+
+